Locking device for clutch control mechanisms



Sept 1943- Y B. CAMERON 2,329,743

LOCKING DEVICE FOR CLUTCH CONTROL MECHANISM Filed March 29, 194iINVENTOR MORTlMER BCAMEHON BY mwqw- ATTORN EY Patented Sept. 21, 1943MECHANISMS I Mortimer B, Cameron, ,Edgewood, Pa., assignor' A to TheWestinghouse Air BrakeCompany, Wilnerding, Pa, a corporation ofPennsylvania Application March 29, 1941, Serial No.'385,873

2 Claims. to]. 188-171).

This invention relates to clutch control mechanismsand more particularlyto means for definin'g 'a chosen -.position of the shifting means ofsuch a mechanism and for securing said' shifting means therein.

In my copending applicationSerial NoI 347,822, filed July 27, 1940,Patent 'No.2;279,3 65,= April 14', 1942, there'is dis'close'da clutchcontrolmech anism embodying a motor which is operative by fluid underpressure to selectively position a clutch in either'one or the other. oftwo drive positions or in a neutral non-operatingposition.

To move the clutch to one-of its drive positions piston means in themotorfis moved by? fluid under pressure to one extreme position. To.move the clutch to the other drive 'position'thepiston means; is movedby fluid 'under pressure to' an opposite extreme" position.To-neut'ralize' the clutch'the motor piston mea'n'sis movable by fluidunder pressure from'either of its extreme positions in the direction ofthe other and a'latch is arranged to arrestv'such movement ina'neutralposition between the two extreme positions.

The latch or locking means disclosed in the above mentioned cop'endingapplication comprises an electromagnet armature which when theelectro-magnet is deenergized is movable by spring" pressure.intolocking relation; with the motor piston means'when'inneutr'alposition for thereby securing the clutch in'its. neutral or nonoperatingposition. *Energization of the electro magnet is adapted to release thearmature from the motor piston means to, provide for operation ofthe'mo'tor to shift the, clutch to its different drive positions. Themotor release (positionof the armature is deflned by engagement withastop Whichin practice is a, part of thezmagnet casing andit has beenfound ,thatin movingto such position the armature, strikes the-stop witha force, which is'liableto causerupture of said casing. This is due tothe well-known fact that the magnetic; pull on the armature increasesvery rapidly as the air gap between ,the armature and its stopagainst-the icasingzireducesso thatat the time 'thereleas'e' position?is reached a 'relatively great"v and possibly destructive force -isobtained. .4. 1

The principal object of the'present invention is the, provision of. 'an'electromagnetxstructure embodying novel means for obviatingtheob'ectionable oharacteristicijust described. Other objects andadvantages will be apparent from the following more detaileddescriptionof the invention; ,1

In the accompanying. drawing;

Fig. 1 is across-sectional view through a'clutch shifting motor and alocking magnet; device rem: bodying' the invention; and ."I Fig. 2 is aview similar tot-a portion of Fig, 1 but showing the locking magnetarmature in its motor releasing position. r a

As shown in the drawing, the, clutchishifting motor employed v for the.purpose .of illustrating one use of the invention, comprises; a-casingI. which" is adapted to be mounted on orotherwise intimately associatedwith the housing (not shown); of a three-position clutch gwhichisadapted to .be.moved'jto its. diiferent'positions through the medium ofa rock shaft 2 extending into the casing I. The casing contains two 01positely disposed reciprocating pistons 3-andj4 which are spaced apart"and connected together by a rod 5. Ashifting arm 6 has one-end.se

cured to the shaft 2 for rocking same. The opposite end of arm 6 isbifurcated and straddles a block"? whichis journaled on a pin ssecuredto "the piston rod 5 intermediate the endsthereof.

The piston 3 has at its outerfaceachamber l0 adapted to beyconnected toa pipe through an opening I I, whilethe pistonA has at its opposite facea chamber-l2 adapted tobe. connected to a difierent pipe through anopening t3. In;use; fluid under. pressure is adapted to-be supplied toone of these chambers, only when the other is vented. -Thus when fluidunder; pressure is supplied tochamber m toacton piston 3, said piston isad-aptedto move towardthev right-hand until pistond contacts one end ofthe casing for thereby-rocking the arm 5 and shaft 2 in a clockwisedirection to move the clutch to-one of, its drive positions. When"fluid under pressure is supplied to the piston chamberlZ to act mp1 ton4, said piston is adapted-to move toward.the left hand until piston3contacts the opposit'eend of the casing for rocking the arm 6 and shaftZin a counterclockwise direction to movethe-clutch to its. other drivingposition.

In order to arrest movement of the pistons 3 and 4 andthereby ofarrnfian'd rockshaft2 in the neutral position shown for therebypositioning the clutch in its neutral'or nOndriVing position,

\ amagnet device I5 is associated with the casing I.

The magnet'device I 5 comprises aninverted cup-shaped section I6 havingits openi end mounted against a base member H which in turn is securedto the motor casing I Thecup; shaped section l6 carries a sleeve-:18having one end secured to a boss I 9 projecting'inwardly from the closedend of the section,-w-hile the other end of, the sleeve engagesqtheendof a shortepsleeve 20 disposed in coaxial relation in the base membarI and having its lower end opening over the top of the piston rod 5.Both of these sleeves are made of non-magnetic material, such as brass,and slidably mounted in the sleeves i a magnet armature 2 l Directlybelow the end of the armature 2| the piston rod 5 is provided with a rib22 eiitending longitudinally thereof between the pistons 3 and 4.Intermediate the ends of this rib is a notch 23 adapted to receive theend of the armature 2 I when the two pistons 3 and 4, arm 6 and shaft?!are in their neutral positions shown. The end of the armature enteringthe notch 23 is tapered and the opposite sides of said notch adaptedto.

ment against the light spring 34, whereby the movement of the armaturewill be slowed down during the remainder of its stroke into contact withthe boss I9 which constitutes a release stop for the armature.

It will be apparent that the relatively light spring 34 which opposes.the movement of the armature providesf-or prompt; release of thearmature from the piston'rod rib 22 upon energization of the magnet. Thebuffer spring 30 then becomes effective to snub the armature so 1 thatthe force with which it strikes against the be engaged by the armatureare-formed at ems-u spending angles in order to provide a contact therib 22. y 7

The armature is provided in one side with a longitudinally extendingslot 35 and carried by the base member 17 and extending into said slotis a pin 26. The armature is adapted to move relative to pin 26 inoperation and said pin is adapted to maintain the lower tapered end ofthe armature in alignment for entering the notch 23 in the piston rodrib 22.

A washer 28 encircles the armature 24 above the piston rod rib 22 and issupported on a pin 2| secured to the armature. This washer constitutes aseat for one end of a buffer springzfl the opposite end of which engagesanLout-turned annulanfiange 3| of a sleeve 32 which is contained withinthe upper end coils of said spring; The sleeve 32 has at its lower endan in-turned annular flange 33 which supports one end of a relativelylight spring 34 the opposite end'of which bears against the base memberI1. I

Contained in the cup-shaped casing liiis a magnet operating coil 36.When this coil is de energized the magnet armature 2|v is adapted to beforced downwardly into engagement with the top of the rib 22 or into thenotch 23 bythe pressure of the relatively light releasespring 34transmitted throughthe sleeve 32 andbufier spring 30 to the spring seator washer 28. The bllfl'er spring 30 having greater compressive forcethan spring 34 merely acts in efiect undenthis condition like a solidconnection between the lighter spring 34 andwasher 28 and may thereforebe expanded to substantially its free height.

When the magnet coil 35 is energized the magnetic attraction between theupper end of the armature 2i and boss 19 extending intothe sleeve l8causes the armature 2 Ho move upwardly and away from the piston stem rib22., During-the initial" portion of tins movement the washer 28 andbuffer spring 30 merely move withthe armature against the opposing forceof the relatively light spring 34 whichjdetermines the degree ofmagnetic force required to effectsuch movement. However, atsubstantially the time the end of the armature moves out of notch 23 inthe piston stem rib 22, at which time the air gap between the armatureresulting-front its initial moveboss 19 will be of such a low degree asnot to cause damage to the magnet housing.

When the ma et coil 36 is again deenergized the buffer spring 3! willinitially act to start the armature 2] moving away from the boss l9, butits action is limited to substantially its free height h of expansionshown in the drawing, after which further movement of the armature isdependent uponthe forceof the relatively lightspringe l.

-Topermit operations of the clutch .Shiitfll motor them'agnetcoil iliiisadapted to beepergized forireleasing the armature 2i from the pistonstem rib 22 in order to permit the pistons 3 or 4 to be operated byfluid. under pressuretor shifting the clutoh'to either .one or the'otherof its driving positionsn When it isidesiredto move the clutch fromeither Poi-its driving positions to its neutrals: non-operatingposition, the magnetcoil B6 'is deenergized at; substantially :ithe timefluid unden-pressureois supplied zto the proper piston chamber 19 or4:2; Asaresult; the armature 2i willjbe urseddownwardly against thepistonrodrib .22 bythe spring 34 so that when the notch 23 the. rib.moves into alignment with the end of thearmatura; as the pistons aremoved in; either one "direction or the'other. said armature will be.forced into-said notch by spring 84 and thereby .arrcstthe pistcnsintheir neutral position shovm for thereby neutralizing theclutchcontrolleduthereby; When it is subsequently desired-to move theiclntch to a driving position the ma'gnet ,coil 35. must-be energized towithdraw thearmature. 2t from the notch 23; as

will beapparent'.rj .1 I

{An inspection of the drawing will show :that the buffer-spring 30becomes effective just 'prior to'the end of the'armature clearing theupper surface of the piston rod rib 22. This isdue to the' fact" that itis difllcult to provide in the limited space available a buffer springhaving the desired characteristics. However, this does not work to thedisadvantage of the device'in any respect and is not objectionable,since it will be noted that thebuifer spring at thetime of contact withthe base member I! is ubstantially at itsfree height and therefore doesnot provide initially an excessive force to oppose thev slight furthermovement of the armature to clear the rib 22. Furthermore, the inertiaof the armature 2| at this'time is suficient to oifset to a certaindegree the initial opposing force of' the bufier spring 3e and it hasbeen found that the armature 21 will promptly clear the piston rod rib22 to permit the desired operation of the motor.

A rod 3'! having one end secured to the upper endot the armature 2|extends through a suitablebore in the boss Hi and upper closed end ofthe magnet casing section [B to the exterior of said casing. A boot 38is mounted over the outer end of the rod3'l and clamped thereto betweentwo washers 39by a nut 40. The outer edge of this boot is contractedaround a rib M on the casing section l6. This boot is provided toexclude foreign matter from the bearing between the rod and casingsection l6 and thereby from the interior of the magnet device.

The outer end of the rod 31 is provided with screw threads to which amanually operated puller (not shown) is adapted to be applied. Thus, incase of failure of the supply of electric current for energizing themagnet, the armature 2! may be pulled manually out of the notch 23 inthe piston rod rib 22 so that bya hand lever (not shown) the clutch maybe shifted manually to any one of its difierent positions. By thisarrangement an operator can move the vehicle to a terminal or the likefor repair.

Summary From the above description it will now be apparent than anarrangement has been provided for counteracting magnetic pull on thearmature of a magnet after a certain degree of movement thereof and toabsorb a portion of the inertia of the armature resulting from itsinitial movement so as to thereby minimize the shock of contact betweenthe armature and its stop. The improved armature snubbing arrangementhas no eifect upon movement of the armature through a desired degree oftravel when the magnet is energized, so that the armature will be justas responsive to provide a desired result as without said arrangement.It will further be apparent that the invention is not limited in use toa clutch shifting motor.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. A magnet device comprising a movable armature movable in onedirection upon energization of said magnet device and spring means foropposing such movement comprising a relatively light spring having acertain compressive force, a heavier spring having a greater compressiveforce, means connecting said springs in series to said armature forrendering the first named spring effective to oppose initial movement ofsaid armature upon energization of said magnet device, and meansoperative after a certain initial movement of said armature to renderthe first named spring ineffective and the second named spring effectiveto oppose further movement of said armature.

2. Means for releasably locking a movable member in a chosen position,said member having a notch, and said means comprising a magnet devicehaving a movable armature arranged to enter said notch for securing saidmember against movement, one spring having a relatively high compressiveforce bearing at one end on said armature, another spring having arelatively light compressive force and hearing at one end against saidmagnet device, means operatively connecting the opposite ends of the twosprings and so arranged as to render the lighter spring effective tourge said armature into said notch upon deenergization of said magnetdevice and to oppose movement of said armature out of said notch uponenergization of said magnet device, the said means connecting saidsprings being arranged as to render the first named spring effective tooppose movement of said armature upon energization of said magnet deviceat substantially the time said armature moves out of said notch.

' MORTIMER B. CAMERON.

